CVE-2021-42144
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedBuffer over-read vulnerability in Contiki-NG tinyDTLS through master branch 53a0d97 allows attackers obtain sensitive information via crafted input to dtls_ccm_decrypt_message().
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceBuffer over-read vulnerability in Contiki-NG tinyDTLS dtls_ccm_decrypt_message() function allows attackers to read beyond allocated buffer boundaries, potentially exposing sensitive information like encryption keys or session data. The flaw is triggered by crafted DTLS input to the CCM decryption routine.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data<= 2018-08-30CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify if tinyDTLS is included in the buildSearch the firmware image, build artifacts, or source code for tinyDTLS library files (such as dtls.c, dtls.h, ccm.c) or the string 'tinyDTLS'. Inspect the project's Makefile or build configuration for references to tinyDTLS.Affected if tinyDTLS is present in the environment and the build configuration includes DTLS support.
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Determine the tinyDTLS versionCheck the version of tinyDTLS by inspecting the source code commit date, version tag, or header file (often in dtls.h or a VERSION file). Compare this date to 2018-08-30.Affected if The tinyDTLS version date is on or before 2018-08-30.
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Verify DTLS protocol support is enabledInspect the project's configuration files (such as contiki-conf.h, project-conf.h, or Makefile) for DTLS enablement flags such as DTLS_ENABLED, WITH_DTLS, or ENABLE_DTLS. Search for any DTLS-related compilation flags.Affected if DTLS is enabled in the configuration and the application uses DTLS for communication.
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Confirm CCM cipher mode is in useSearch the configuration or source code for CCM-related definitions such as CCM, DTLS_CCM, or dtls_ccm_decrypt_message. Check whether the DTLS cipher suite includes CCM-based variants.Affected if The DTLS implementation uses CCM cipher mode for encryption/decryption.
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Locate the vulnerable dtls_ccm_decrypt_message functionSearch the tinyDTLS source code for the function dtls_ccm_decrypt_message and verify its bounds checking implementation. Identify if this function is called by the application's DTLS handling code.Affected if The dtls_ccm_decrypt_message function exists in the codebase and is invoked during DTLS message processing.
The environment is affected if it uses Contiki-NG with tinyDTLS version dated on or before 2018-08-30, has DTLS enabled, and utilizes CCM cipher mode for DTLS communications.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpdate tinyDTLS to a patched version that includes proper bounds validation in dtls_ccm_decrypt_message(). For constrained IoT devices, ensure secure OTA update mechanisms are in place for deployment.
- Consultation6.0 h
- Implementation12.0 h
- Testing10.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-42144 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-42144 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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